Aux water pump for 1980 300SD

Does anyone have any advice on where to get a good aux water pump for a
1980 300SD? This is the little electric booster pump that sits next to
the climate control servo.

I've been through 3 of them from Adsit Company and they are pure crap.
Fortunately, they kept replacing them under warranty, but even then, I
think all 3 only lasted less than a year. They all had small slow
leaks around the shaft right out of the box. The last one, I decided
to just live with it. Then driving along one fine day I heard the most
horribly squealing from under the hood, like the squirrels were all
fighting with each other. Turns out the bearing on the shaft had
completely failed and it was just spinning around and flopping all
over.
The Adsit ones were no name cheapo ones for about $90. I see Bosch
makes one two, which I assume would be better, but thought I'd ask if
anyone has any other info.
Thanks
Chet

I own the same model and have replaced a few of these pumps. The salvage
yard pumps are a bit cheaper and leak a bit but work. All leak at their
shaft seal and eventually the motor shorts out and the CC is dead.
Disconnect the pump and replace two fuses and CC works again.
I drove for many months with the aux. pump disconnected and didn't
notice any difference in the heater's performance - it started running
about the same driving distance after cold start as always. The pump
only runs in a relatively narrow temperature range, not continually.
You may try that and replace the pump with a piece of pipe if the heat
output is satisfactory.
That's what I intend to do this week when I install a digital
replacement servo & amplifier ($699, sold by Performance Products). That
and no pump should hopefully bring the original Rube Goldberg CC system
in this car up to modern standards.

Thanks for the advice. I don't think it's worth it to try to find a
salvage one. The time spent trying to find one vs the chance it would
actually last, etc just aren't worth it. I'm either going to go with
the Bosch one for $140 or else bypass it. I agree with TG, that it
doesn't seem to make much diff having it in there. I think the biggest
diff would be for situations where you started the car when it was real
cold and left it idling instead of driving off soon. In that case, you
might get heat noticeably faster, but otherwise it doesn't seem to make
too much diff.
TG, let us know how you make out with that digital replacement for the
glockenspiel gizmo! I have the rebuilt aluminum one with the fix it
forever for $100 guarantee. It's about 18 months now and works great
so far.

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